Prevalence and screening of active tuberculosis in a prison in the South of Brazil

SETTING: Tuberculosis (TB) remains a challenge in Brazil, particularly among prison inmates. OBJECTIVE: To assess TB prevalence by active case finding in a public prison in southern Brazil. DESIGN: Prison inmates were screened for TB using the presence of cough and chest X-ray (CXR) from October 2014 to August 2016. Presence of cough, irrespective of duration, and abnormal CXRs were further investigated using laboratory tests. RESULTS: Of 10 326 inmates screened, 196 had confirmed TB (1898/100 000 inmates screened). At the first screening, 1759 inmates presented with cough only, 16 of whom had TB; among those with only abnormal CXR (n = 1273), 92 had TB. Xpert was positive in 155 patients, and negative in 15; these results were confirmed using culture. The remaining 26 patients did not undergo Xpert testing and were confirmed using microscopy (27%), culture (42%) or both (31%). CONCLUSION: The combined use of symptom screening (cough) and CXR was much more effective in maximising TB yield than using either method alone. If patients presenting with cough alone had not been investigated, 10% of TB patients would have been missed; if those with abnormal CXR but no cough had not been investigated, 51% of TB patients would have been missed. We detected high TB prevalence in this prison by using active case finding.